Challenges of talent development in alpine ski racing: a narrative review.

Alpine ski racing is one of the most popular sports in many countries; nevertheless, selection disadvantages and severe injuries result in high dropout rates. In this review we summarize existing knowledge about the specific challenges associated with selection bias and injuries, and their effects on talent development in ski racing. The relative age effect (RAE) appears in all age categories of national Austrian and international alpine ski racing. Relatively younger athletes seem to only have a chance for selection if they are early maturing. Talent selection processes should consider both the biological maturity status as well as the relative age; additionally, a competition system based on a rotating cut-off date might contribute to a reduction of RAE. Youth and adolescent ski racers report lower injury rates compared to World Cup athletes. The knee was the most affected body part in relation to traumatic injuries. The most frequently reported overuse injuries were knee pain (youth) and low back pain (adolescent level). Athlete-related modifiable risk factors were core strength, neuromuscular control, leg extension strength and limb asymmetries. Based on these findings, prevention measures should be expanded to contribute to long-term injury prevention. In future research more multi-disciplinary, longitudinal studies should be performed.

The Role of a Relative Age Effect in the 7th International Children's Winter Games 2016 and the Influence of Biological Maturity Status on Selection.

The aim of this study was to analyse the role of a relative age effect (RAE) and to investigate the influence of biological maturity status on the RAE at the 7th International Children`s Winter Games. The birth dates of all 572 participants (365 males, 207 females) were analysed, and the biological maturity status of 384 athletes (243 males, 141 females) was assessed by the age at peak height velocity (APHV) method. A RAE was present in the total sample (χ2 = 67.81; p < 0.001), and among both male (χ2 = 49.02; p < 0.001) and female athletes (χ2 = 37.00; p < 0.001) as well as for strength- (χ2 = 56.46; p < 0.001), endurance- (χ2 = 20.48; p = 0.039) and technique-related types of sports (χ2 = 20.48; p = 0.041). No significant differences in biological maturity status were present between the male athletes of single relative age quarters. Among the female athletes a significant difference was present (F = 5.94, p < 0.001); relatively younger female athletes had significantly lower values in the APHV, which indicated that they were maturing earlier. However, when dividing the athletes into normal, early and late maturing athletes, it could be seen that among the relatively younger athletes, hardly any late maturing athletes were present. These findings revealed that relatively younger athletes seemed to only have a chance for selection if they were early maturing, whereas relatively older athletes had an increased likelihood for selection independent of their biological maturity status. In the future, the relative age and the biological maturity status should be considered in the talent development system for various types of winter sport, to contribute to more fairness and to not discriminate against relatively younger and less mature athletes.

Functional assessments for decision-making regarding return to sports following ACL reconstruction. Part I: development of a new test battery.

PURPOSE: Return to activity remains the most common concern following an injury. To facilitate the decision regarding a patient's return to sport, we developed a standardized and easy-to-use test battery to enable an objective evaluation of knee function. METHODS: The test battery consisted of seven functional tests: the two-leg stability test, one-leg stability test (OL-ST), two-leg countermovement jump (CMJ), one-leg CMJ (OL-CMJ), plyometric jumps, speedy test and quick feet test. For each test, the reliability was determined based on the intraclass correlation coefficient. For all one-leg tests, the limb symmetry index (LSI) was calculated. RESULTS: All tests showed a moderate-to-high reliability. Normative data from 434 participants were included in the analysis. The subjects were categorized according to age as follows: children (10-14 years), youth (15-19 years), young adults (20-29 years) and adults (30-50 years). The establishment of the functional test values allowed the classification into five normative categories. The LSI for the OL-ST (98 %) indicated a better performance of the non-dominant leg. In contrast, high LSI values were found for the OL-CMJ (124 %), indicating a better performance of the dominant leg. CONCLUSION: Each test was found to be reliable and simple to perform. The better performance of the non-dominant leg in stability tasks must be considered when interpreting side-to-side differences. The established norm data from healthy individuals of each test battery represents an important basis for a clinical setting. Test results from an ACL-reconstructed patient should be at least classified as a functionally average outcome to support a safe return to sports. LEVEL OF EVIDENCE: IV.

The relative age effect and the influence on performance in youth alpine ski racing.

The relative age effect (RAE), which refers to an over representation of athletes born early in a selection year, recently was proven to be present in alpine skiing. However, it was not made apparent whether the RAE exists as early as at the youngest level of youth ski racing at national level, nor whether the relative age influences racing performance. As a consequence, the purpose of the present study was twofold: first, to examine the extent of the RAE and second, to assess the influence the relative age has on the overall performance at the youngest levels of youth ski racing. The study included the investigation of 1,438 participants of the Austrian Kids Cup and 1,004 participants of the Teenager Cup at the provincial level, as well as 250 finalists of the Kids Cup and 150 finalists of the Teenager Cup at the national level. Chi²-tests revealed a highly significant RAE already at the youngest level of youth ski racing (Kids Cup) at both the provincial and national levels. There are not again favorably selected the relatively older athletes from the first into the second level of youth ski racing (Teenager Cup). Among the athletes of the Kids Cup, the relative age quarter distribution differed highly significantly from the distribution of the total sample with an over representation of relatively older athletes by comparison taking the top three positions. The data revealed that relative age had a highly significant influence on performance. This study demonstrated that the RAE poses a problem as early as the youngest level of youth ski racing, thereby indicating that many young talented kids are discriminated against, diminishing any chance they might have of becoming elite athletes despite their talents and efforts. The RAE influences not only the participation rate in alpine skiing, but also the performances. As a result, changes in the talent development system are imperative. Key pointsThe relative age influences not only the participation in youth ski racing, but also the performance.The relative age effect is present in all age categories in alpine skiing at national, as well as international level; this indicates that there is a severe loss of talents.From an ethical point of view, the entire talent identification and development process in alpine ski racing is discriminatory against young talented kids; consequently, this process should be reevaluated and changed to reduce the impact of RAE on young alpine ski racers in the future.The system for the competition category classification based on a rotating cut-off-date appears to be an interesting proposal for the reduction of the relative age effect in alpine skiing as well.

The role of a relative age effect in the first winter Youth Olympic Games in 2012.

BACKGROUND: Owing to the separation into age groups at the first winter Youth Olympic Games (YOG), athletes differed in age by up to two years, leading to a potential relative age effect (RAE). OBJECTIVE: The purpose of this study was to define the role of the RAE in the first winter YOG with regard to sex, type of sport and performance. METHODS: The birth dates and anthropometric data of all 1021 athletes (557 male, 464 female, 14-19 years old) participating in 15 sports were analysed. A χ(2) test was used to assess the difference between the observed and expected birth distributions. ANOVA (analysis of variance) and Kruskal-Wallis analyses were used to investigate differences in anthropometrics. RESULTS: The birth date distribution of the overall sample was significantly different from an equal distribution, with an over-representation of athletes born shortly after the cut-off date (χ(2)=284.7, p<0.001). A significant RAE was found in both male (χ(2)=245.1, p<0.001) and female competitors (χ(2)=74.6, p<0.001). An analysis based on the type of sport showed an RAE in all categories (strength-χ(2)=229.9, p<0.001, endurance-χ(2)=60.4, p<0.001 and technique-related sports χ(2)=25.2, p=0.001). Relatively older competitors were also over-represented among medal winners (χ(2)=47.9, p<0.001). Relatively older male competitors were significantly taller (p=0.005) and heavier (p<0.001) than younger competitors. No differences were found in female competitors. CONCLUSIONS: The results suggest that relative age had a highly significant influence on participation in various sports regardless of sex. A possible strategy to reduce the RAE would be a fixed quota for each birth year within the two-year age group across events.

The relationship between ACL injuries and physical fitness in young competitive ski racers: a 10-year longitudinal study.

BACKGROUND: Epidemiological studies have shown a high incidence of anterior cruciate ligament (ACL) injuries among competitive alpine skiers. Little is known regarding modifiable risk factors in young skiers. There are still uncertainties in gender-related risk factors. OBJECTIVE: The purpose of this study was to determine the relationship between ACL injuries and internal risk factors. METHODS: Retrospective data analyses were performed based on a group of 175 female and 195 male alpine ski racers between the ages of 14 and 19 years. The athletes underwent physical testing annually from 1996 to 2006. Z score transformations normalised the age groups. Multivariate binary logistic regressions were calculated for men and women separately to detect significant predictors of ACL ruptures. t Tests were computed to reveal the differences in test scores between injured and non-injured athletes. RESULTS: A total of 57 (15%) ACL injuries occurred. The female-male risk ratio (RR) was higher in females (2.3, 95% CI 1.3 to 4.2). Z scores for relative leg force, ratio of absolute core flexion to extension force, relative core strength and reactive strength index were predictive variables for men. Z scores of all of these predictive variables except relative leg force were higher in the non-injured group. The ratios of absolute flexion to extension force and absolute core strength were predictive covariates for women. Z scores for absolute core strength were higher in the non-injured group. CONCLUSIONS: The risk of ACL injury was greater in female athletes. The findings suggest that core strength is a predominant critical factor for ACL injuries in young ski racers.

Training load characteristics and injury and illness risk identification in elite youth ski racing: A prospective study.

PURPOSE: The study aimed to investigate the role of training load characteristics and injury and illness risk in youth ski racing. METHODS: The training load characteristics as well as traumatic injuries, overuse injuries, and illnesses of 91 elite youth ski racers (age = 12.1 ± 1.3 years, mean ± SD) were prospectively recorded over a period of 1 season by using a sport-specific online database. Multiple linear regression analyses were performed to monitor the influence of training load on injuries and illnesses. Differences in mean training load characteristics between preseason, in-season, and post-season were calculated using multivariate analyses of variance. RESULTS: Differences were discovered in the number of weekly training sessions (p = 0.005) between pre-season (4.97 ± 1.57) and post-season (3.24 ± 0.71), in the mean training volume (p = 0.022) between in-season (865.8 ± 197.8 min) and post-season (497.0 ± 225.5 min) and in the mean weekly training intensity (Index) (p = 0.012) between in-season (11.7 ± 1.8) and post-season (8.9 ± 1.7). A total of 185 medical problems were reported (41 traumatic injuries, 12 overuse injuries, and 132 illnesses). The weekly training volume and training intensity was not a significant risk factor for injuries (p > 0.05). Training intensity was found to be a significant risk factor for illnesses in the same week (ß = 0.348; p = 0.044; R²â€¯= 0.121) and training volume represents a risk factor for illnesses in the following week (ß = 0.397; p = 0.027; R²â€¯= 0.157). CONCLUSION: A higher training intensity and volume were associated with increased illnesses, but not with a higher risk of injury. Monitoring training and ensuring appropriate progression of training load between weeks may decrease incidents of illness in-season.

Changes in Anthropometric and Fitness Characteristics Over a Decade of Young Elite Alpine Ski Racers.

PURPOSE: The aim of this study was to evaluate whether anthropometric and fitness characteristics have changed between former and current elite male and female Austrian young ski racers (U11-U15). METHODS: A battery of anthropometric, general, and skiing-specific fitness tests was conducted annually. In total, 1517 participants (846 males, 671 females) who were tested in 2005-2009 ("former athletes" n = 805) and 2015-2019 ("current athletes" n = 712) were included. Independent t tests and Cohen d were calculated to compare the two 5-y periods, separated by sex and age group. The level of significance was set at P < .05. RESULTS: No significant change in anthropometric characteristics was found over the decade. Current young ski racers performed significantly better in the maximal core flexion strength test in all age categories (ES = 0.88-1.50; P < .02). Core extension strength values were higher in current male U12 and female U12 and U13 athletes (ES = 0.54-0.71; P < .01) and better postural stability values in the lateral direction were found in the age categories U12 and U14 (ES = 0.36-0.68; P < .05), as well as in the forward/backward direction in the age categories U12-U14 (ES = 0.38-1.12; P < .03). Lower-leg extension strength values were apparent in the current U13-U15 age categories (ES = 0.36-1.03; P ≤ .001) and lower drop-jump reactive strength indices in the U13-U15 male athletes (ES = 0.49-0.80; P < .01). CONCLUSIONS: Current and former young ski racers differ significantly in some fitness parameters, which might lead to the assumption that some aspects (such as core strength) have gained more focus in athletic training during the last years compared with 15 y ago.

An overview of recent application of medical infrared thermography in sports medicine in Austria.

Medical infrared thermography (MIT) is used for analyzing physiological functions related to skin temperature. Technological advances have made MIT a reliable medical measurement tool. This paper provides an overview of MIT's technical requirements and usefulness in sports medicine, with a special focus on overuse and traumatic knee injuries. Case studies are used to illustrate the clinical applicability and limitations of MIT. It is concluded that MIT is a non-invasive, non-radiating, low cost detection tool which should be applied for pre-scanning athletes in sports medicine.

Relationship of Changes in Physical Fitness and Anthropometric Characteristics over One Season, Biological Maturity Status and Injury Risk in Elite Youth Ski Racers: A Prospective Study.

Alpine ski racing is a sport with a high risk of injuries. In order to contribute to the longitudinal career development of young athletes, prevention measures should be elaborated. Therefore, the aim of the present study was to investigate prospectively the role of biological maturity status, and changes in anthropometric characteristics and physical fitness parameters over one season in elite youth ski racers younger than 15 years. Eighty-nine elite youth ski racers (39 females, 50 males), aged 10-14 years (mean age: 12.1 ± 1.3), were investigated. Anthropometric characteristics and physical fitness parameters were assessed prior and after the winter season; traumatic and overuse injuries were recorded over the 32 weeks. Binary logistic regression analyses (R² = 0.202-0.188) revealed that the biological maturity (Wald = 4.818; p = 0.028), and changes over the season in the jump agility test (Wald = 4.692; p = 0.03), in body height (Wald = 6.229; p = 0.013), and in leg length (Wald = 4.321; p = 0.038) represented significant injury risk factors. Athletes who could improve their jump agility performance more, had smaller changes in the anthropometric characteristics and who were closer to their peak height velocity were at a lower injury risk. In the context of injury prevention, regular neuromuscular training should be incorporated, and phases of rapid growth have to be considered.

Did the Relative Age Effect Change Over a Decade in Elite Youth Ski Racing?

The relative age effect (RAE) represents an asymmetry in birth quarter distribution, favoring athletes born early in the selection year and discriminating against late born athletes. The RAE was proven to be present in all age categories of national and international levels of alpine ski racing. Due to the existence of the RAE in all categories, it can be assumed that a selection error takes place favoring early born and early maturing youth ski racers. However, whether selection strategies have changed during the last years due to the high amount of research done in this field, has not been investigated so far in this sport. Therefore, the aim of the present study was to assess whether the magnitude of the RAE in youth ski racers aged 10-14 years has changed during the last decade by comparing the periods 2005-2009 ("former" athletes) and 2015-2019 ("current" athletes). Pupils of a well-known skiing-specific secondary modern school as well as members of the provincial ski team, who all competed at national levels, were included in the study. Next to the birth months, anthropometric characteristics (body height, weight, body mass index) were assessed. Chi-square tests were used to compare differences between the observed and expected relative age quarter distributions across five age categories (U11-U15). Additionally, Kruskal-Wallis-H-Tests were performed to assess differences in anthropometric characteristics between athletes of the four relative age quarters. Mann-Whitney U-Tests were performed to assess possible differences in anthropometric characteristics between former and current ski racers. A highly significant RAE was present in both former [χ2 (3, 764) = 60.36; p < 0.001; ω = 0.31] and current youth ski racers [χ2 (3, 702) = 43.13; p < 0.001; ω = 0.29] with an over-representation of athletes of Q1 (30.3-34.2%) and a clear under-representation of athletes of Q4 (14.8-15.0%). Generally, results indicated no change in the magnitude of the RAE in youth alpine ski racing over the past 10-15 years, emphasizing the robust nature of this phenomenon. No significant differences were found in any of the anthropometric characteristics between athletes of the four relative age quarters in both former and current athletes, indicating that relatively younger athletes of the last relative age quarter seem to have to have advanced anthropometric characteristics for being selected. Changes in the talent selection process should be performed to reduce the impact of the RAE.

Effects of Visual and Auditory Perturbations on Ski-Specific Balance among Males and Females-A Randomized Crossover Trial.

Injuries in skiing show sex-specific differences, especially when visual perception is reduced. Reduced visual perception impairs balance, which plays an important role in avoiding skiing injuries. However, males and females might cope differently with reduced visual perception. Thus, the aim of this study was to evaluate sex-related effects of environmental perturbations (reduced visual perception and listening to music) on ski-specific balance. Using a crossover design, ski-specific balance was tested in 50 young adults (50% female) in four conditions: with and without listening to music and/or with and without reduced visual perception (ski goggles with occlusion foil). A four × two (condition by sex) mixed ANOVA revealed a significant condition by sex interaction, partial η² = 0.06. Females showed an increase in balance from the condition without music/with normal visual perception to the condition with music/with normal visual perception, while males showed a decrease. Balance was significantly higher in females compared to males, partial η² = 0.31. The findings suggest that balance is affected differently by environmental perturbations in females and males. However, the differences observed were not in line with our initial hypotheses, which might be because the model was too simplistic for how visual/auditory perturbations may affect balance.

Limb symmetry index in competitive alpine ski racers: Reference values and injury risk identification according to age-related performance levels.

PURPOSE: The aims of this study were to assess differences of limb symmetry index (LSI) in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers. METHODS: The study (Study 1) included 285 high-level competitive ski racers (125 females, 160 males) of 3 age-related performance levels and based on the school system: 95 youth (10-14 years, secondary modern school), 107 adolescent (15-19 years, grammar school), and 83 elite athletes (20-34 years). To investigate the second aim (Study 2), 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests (strength related: one-leg counter movement jump (OL-CMJ) and one-leg isometric/isokinetic press strength test (OL-ILS); coordination related: one-leg stability test (OL-ST) and one-leg speedy jump test (OL-SJ)). The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted. RESULTS: There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests: the OL-CMJ (χ²(2, 285) = 9.09; p = 0.01) and the OL-ILS (χ²(2, 285) = 14.79; p < 0.01). The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers (Wald = 7.08; p < 0.01). No significant risk factors were found for overuse injuries. CONCLUSION: Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of <10% for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks (strength vs. coordination related) rather than on generalizations, and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.

[Factors Associated with Safety Knowledge on Alpine Ski Slopes]. / Einflussfaktoren auf das sicherheitsrelevante Wissen auf der Skipiste.

BACKGROUND: The jurisdiction after a winter sport accident including a third party fault considers the 10 rules for safe skiing/snowboarding introduced by the International Ski Federation (FIS) to clarify the question of liability. A previous study revealed that beginners, young skiers and those who were not local residents displayed insufficient safety knowledge in given situations. The aim of this study was to evaluate additional factors associated with safety knowledge on ski slopes, e. g. type of winter sport, helmet use, risk taking behavior, and a previous injury occurred on a ski slope. METHODS: People participating in snow sports were interviewed in March 2012 during 2 weekends in 5 Austrian ski areas, using a standardised questionnaire. Participants had to correctly answer 12 statements according to safety knowledge based on the 10 FIS rules. RESULTS: A total of 602 persons (67 % skiers) with a mean age of 32.8 ±â€Š14.6 (Range: 8 - 77) years were interviewed. In total, 12 and 11 statements were correctly answered by 14 % and 25 % participants, respectively. A total of 19 - 38 % of participants did not answer those statements correctly, including appropriate behaviour on the ski slope (overtaking, priority, stopping, and adapting speed). Significant differences in safety knowledge were found with regard to the type of sport performed, gender, age classes, skill level, frequency of winter sport participation per season, and previous injury. CONCLUSION: Safety knowledge in this study was significantly lower among snowboarders, females, the youngest age group, beginners, and persons without a previous injury.

Sex Differences in Balance Among Alpine Ski Racers: Cross-Sectional Age Comparisons.

Although balance is a key ability in the strength demands of alpine ski racing, affecting both performance and injury prevention, few studies have examined balance or related sex differences among still-maturing athletes. In this 10-year study, we investigated cross-sectional balance performances at different age periods of a representative sample of over 500 11-18-year-old elite skiers of both genders. Participants performed balance tests using the MFT S3-Check. Left-right and forward-backward movements were used to calculate sensory and symmetry balance scores, which were both incorporated into a stability score. Mann-Whitney U tests assessed gender-specific differences by age-group with a significance level set at p < .05. Results showed gender differences only on forward-backward measurements for 14-16-year-olds, with females showing better stability and sensory (but not symmetry) scores than males. Thus, gender interacted with age and maturation to influence balance ability in these participants. Additionally, these rare 10-year data support coaches in their training and talent development of maturing athletes by providing important sport-, age-, and gender-specific normative comparison data for individual trainees.

Trunk Strength Characteristics of Elite Alpine Skiers - a Comparison with Physically Active Controls.

Core muscle imbalances and weak trunk strength are relevant for injury prevention and performance. Information regarding core strength requirements and ideal flexion/extension ratios in alpine skiing is limited. We aimed to compare trunk strength capacities in elite alpine skiers with those of a matched control group. The concentric maximal trunk flexion and extension of 109 elite skiers and 47 active controls were measured at 150°/s in a ballistic mode using the CON-TREX® TP 1000 test system. The relative flexion peak torque was higher in male ski racers (p = 0.003; 2.44 ± 0.30 Nm/kg) than in the controls (2.32 ± 0.42 Nm/kg). The relative peak torque for extension was 4.53 ± 0.65 Nm/kg in ski racers and 4.11 ± 0.52 Nm/kg in the controls (p = 0.001). Female athletes were significantly stronger in both, relative flexion force (p = 0.006; skiers 2.05 ± 0.22 Nm/kg; controls 1.74 ± 0.28 Nm/kg) and relative extension force (p = 0.001; skiers 3.55 ± 0.53 Nm/kg; controls 3.14 ± 0.48 Nm/kg). No significant differences were found in the ratios of flexion to extension forces in females and males. Ski racers are engaged in extensive strength training for both leg and trunk muscles, which explains the higher peak values. Both groups indicated a low ratio from 0.54-0.59, which represents high trunk extensor muscles strength relative to flexor muscles.

Long-Term Athletic Development in Youth Alpine Ski Racing: The Effect of Physical Fitness, Ski Racing Technique, Anthropometrics and Biological Maturity Status on Injuries.

Alpine ski racing is known to be a sport with a high risk of injuries. Because most studies have focused mainly on top-level athletes and on traumatic injuries, limited research exists about injury risk factors among youth ski racers. The aim of this study was to determine the intrinsic risk factors (anthropometrics, biological maturity, physical fitness, racing technique) for injury among youth alpine ski racers. Study participants were 81 youth ski racers attending a ski boarding school (50 males, 31 females; 9-14 years). A prospective longitudinal cohort design was used to monitor sports-related risk factors over two seasons and traumatic (TI) and overuse injuries (OI). At the beginning of the study, anthropometric characteristics (body height, body weight, sitting height, body mass index); biological maturity [status age at peak height velocity (APHV)]; physical performance parameters related to jump coordination, maximal leg and core strength, explosive and reactive strength, balance and endurance; and ski racing technique were assessed. Z score transformations normalized the age groups. Multivariate binary logistic regression (dependent variable: injury yes/no) and multivariate linear regression analyses (dependent variable: injury severity in total days of absence from training) were calculated. T-tests and multivariate analyses of variance were used to reveal differences between injured and non-injured athletes and between injury severity groups. The level of significance was set to p < 0.05. Relatively low rates of injuries were reported for both traumatic (0.63 TI/athlete) and overuse injuries (0.21 OI/athlete). Athletes with higher body weight, body height, and sitting height; lower APHV values; better core flexion strength; smaller core flexion:extension strength ratio; shorter drop jump contact time; and higher drop jump reactive strength index were at a lower injury risk or more vulnerable for fewer days of absence from training. However, significant differences between injured and non-injured athletes were only observed with respect to the drop jump reactive strength index. Regular documentation of anthropometric characteristics, biological maturity and physical fitness parameters is crucial to help to prevent injury in youth ski racing. The present findings suggest that neuromuscular training should be incorporated into the training regimen of youth ski racers to prevent injuries.

Injuries and illnesses in a cohort of elite youth alpine ski racers and the influence of biological maturity and relative age: a two-season prospective study.

BACKGROUND: Studies on injuries and illnesses involving youth ski racers younger than 15 years are lacking in the literature. The aim of this study was prospectively to assess the incidence, prevalence, and severity of traumatic and overuse injuries, as well as illnesses of elite youth ski racers with regard to sex, biological maturity status, and relative age. SUBJECTS AND METHODS: A prospective, longitudinal cohort design was used to monitor the anthropometrics, training characteristics, traumatic and overuse injuries, and illnesses of 82 elite youth ski racers (51 males, 31 females, age 9-14 years) over 2 consecutive years. The exact training exposure (skiing and athletic) was recorded. Relative age and estimated biological maturity status were assessed. RESULTS: Relatively low injury incidence or prevalence (traumatic, 0.86/1,000 hours of training; overuse, 0.28/1,000 hours) and comparably high illness prevalence (2.4/athlete) were reported. The knee was the most commonly affected body part (traumatic injuries 36.5%, overuse injuries 82%). A high number of bone fractures were revealed (46%), while no stress fractures occurred; 66% of the illnesses were respiratory tract infections. No differences were found between males and females, the differing maturity groups, or relative age quartiles. Early-maturing athletes had comparably low traumatic and overuse-injury rates. Relatively younger athletes had low traumatic injury rates. CONCLUSION: The injury-prevention measures implemented in the training process of youth ski racers seem to contribute to a low incidence of injury. Biological maturity status should be considered in the training process to prevent injuries in late-maturing athletes.

The Role of a Relative Age Effect in the 12th Winter European Youth Olympic Festival in 2015.

The aim of this study was to define the role of the relative age effect in the 12th Winter European Youth Olympic Festival 2015. The birth dates of all 899 participants and anthropometric data of 655 participants were analyzed. A significant relative age effect was present in the total sample and among the male athletes but not in the female athletes. Additionally, a significant relative age effect was present in strength- and endurance-related sports but not in technique-related sports. Statistically significantly more older athletes won medals. Relative age had a strong influence on participation in strength- and endurance-related sports as well as on performance.